U.S. patent number 5,660,841 [Application Number 08/636,031] was granted by the patent office on 1997-08-26 for process for preparation of an insect-active assembly.
Invention is credited to Paul Kraft.
United States Patent |
5,660,841 |
Kraft |
August 26, 1997 |
Process for preparation of an insect-active assembly
Abstract
An improved method is provided for preparing an insect-active
assembly which can provide insect repellency, insecticidal action,
or both and which is adapted to be directly affixed to the garment
worn by a person. The assembly is comprised of a polymeric body
which contains an insect-active composition, as a volatile
plasticizer, which, over time, migrates from the polymeric body to
provide the desired degree of insect-active action. The improvement
consists of preparing the assembly at low temperatures thus
preventing losses of the insect-active component to the
environment, during processing under conditions employed in the
prior art. A key element of this improved process is the use of a
thermoplastic latex in place of thermoplastic resins or polymers
used in earlier versions of assembly preparation. The thermoplastic
latices, which have been plasticized with the insect-active
composition, can readily be dried at low temperatures, to form the
assembly.
Inventors: |
Kraft; Paul (Spring Valley,
NY) |
Family
ID: |
24550098 |
Appl.
No.: |
08/636,031 |
Filed: |
April 22, 1996 |
Current U.S.
Class: |
424/403; 424/409;
424/411 |
Current CPC
Class: |
A01N
25/18 (20130101); A01N 25/34 (20130101); A01N
37/18 (20130101); A01N 37/18 (20130101); A01N
53/00 (20130101); A01N 31/02 (20130101); A01N
25/34 (20130101); A01N 25/10 (20130101); A01N
37/18 (20130101); A01N 2300/00 (20130101) |
Current International
Class: |
A01N
25/34 (20060101); A01N 37/18 (20060101); A01N
25/18 (20060101); A01N 025/34 () |
Field of
Search: |
;424/403,411,409 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Page; Thurman K.
Assistant Examiner: Shelborne; Kathryne E.
Attorney, Agent or Firm: Kraft, Esq.; Paul
Claims
I claim:
1. An improved process for the preparation of an insect-active
assembly which comprises a polymeric body which contains a volatile
insect-active composition as a volatile plasticizer therein, said
polymeric body being adapted to be directly affixed to a garment
worn by a person, wherein the improved process comprises:
(a) preparing said assembly from said polymeric body derived from a
thermoplastic latex,
(b) blending said insect-active composition into said thermoplastic
latex, by means of agitation or as an aqueous emulsion or
suspension, as a plasticizer therein,
(c) casting a uniform 0.30 to 50 mil thickness coating of said
thermoplastic latex, which contains said insect-active composition
therein, on a non-stick release type surface,
(d) allowing said plasticized thermoplastic latex coating, which
contains said insect-active composition therein, to coalesce and
dry into a film or sheet assembly at temperatures that range
between 15 and 100 degrees centigrade; to form said polymeric
body,
(e) shaping said polymeric body, which contains the insect-active
plasticizer composition therein, into said assembly configuration
that can be affixed to garments worn by a person.
2. The process of claim 1 wherein said assembly is configured so
that it is adapted to be directly affixed to the garment without
separate attachment means.
3. The process of claim 1 wherein said assembly has a separate
means attached to the polymeric body which is intended to be
directly affix to a garment worn by a person.
4. The process of claim 3 wherein the means to affix the polymeric
body to a garment comprises an adhesive coating on the polymeric
body.
5. The process of claim 3 wherein the means to directly affix the
polymeric body to a garment comprises components of a hook-and-loop
fastener.
6. The process as claimed in claim 1 wherein the polymeric body is
formed from a thermoplastic polymer or copolymer latices selected
from the group consisting of, PVC and it's copolymers, CPVC and
it's copolymers, ABS, styrene acrilonitrile copolymers, butadiene
acrylonitrile coplymers, acrylate and methacrylate polymers and
coplymers, vinyl acetate acrylic polymers and coplymers, ethylene
and propylene polymers and coplymers, and vinyl acetate olefins
polymers and copolymers.
7. The process of claim 1 wherein the thermoplastic polymer latex
is a vinyl chloride-vinylidene chloride copolymer latex.
8. The process of claim 1 wherein the thermoplastic polymer latex
is a vinyl chloride-acrylic copolymer latex.
9. The process of claim 1 wherein the thickness of said polymeric
body containing the insect-active composition therein, upon drying,
varies from 0.20 mils to 30 mils.
10. The process of claim 1 wherein the level of said insect-active
composition in said polymeric body varies from 1 phr to 100
phr.
11. The process of claim 1 wherein the level of said insect active
plasticizer composition in the polymeric body varies from 15 phr to
50 phr.
12. The process of claim 1 wherein said insect-active composition
in the polymeric body is composed of N,N'-diethyltoluamide ("DEET")
used alone or in combinations with naturally occurring or synthetic
pyretherins or in combination with 2-Ethyl-1,3 Hexanediol; which
are efficacious in repelling or killing various species of, ticks,
mosquitoes, flys, bees, hornets, yellow jackets, wasps and biting,
stinging or blood sucking insects.
13. The process of claim 1 wherein said insect-active composition
in the polymeric body is a naturally occurring and or synthetic
pyretherins.
14. The process of claim 1 wherein the insect-active composition in
said polymeric body is composed of blends of 0.5% to 99.5% of
N,N'-diethyltoluamide ("DEET") and 99.5% to 0.5% of naturally
occurring or synthetic pyretherins and the level of said
insect-active composition in said polymeric body varies from 1 phr
to 100 phr.
15. The process of claim 1 wherein the insect-active composition in
said polymeric body is composed of blends of 50% of
N,N'-diethyltoluamide ("DEET") and 50% of naturally occurring or
synthetic pyretherins and the level of said insect-active
composition in said polymeric body 50 phr.
16. An insect-active assembly which comprises a polymeric body
containing a volatile insect-active composition as a volatile
plasticizer therein, said polymeric body being derived from a
thermoplastic latex which has been plasticized with said
insect-active composition, which upon drying yields said assembly;
which can be adapted to be directly affixed to a garment worn by a
person.
Description
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an improved method of
manufacturing an insect-active assembly which can be attached to
the garments of a person and which has "insect active"
characteristic. The term insect active as used in the present
specifications is intended to indicate that the article functions
in regard to insect repellency, insecticidal action, or a
combination of both, when placed in the intended environment on the
garment of a person.
This invention specifically involves an improved process for
preparing an insect-active assembly comprising a polymeric body
which contains an insect-active composition, as a volatile
plasticizer, which over time migrates from the polymeric body to
provide the desired degree of insect-active action. The assembly
can be affixed directly to the garment of a person by a variety of
means including adhesive coatings and hook-and-loop fasteners. A
major advantage of such an assembly is that it provides a degree of
insect-activity without direct skin contact with the insect active
agents; which may be physiologically harmful.
2. Description of Prior Art
U.S. Pat. No. 4,752,477, which is incorporated by reference,
describes an assembly comprising a polymeric body which, contains
an insect-active composition, which acts a volatile plasticizer.
Over time the insect-active composition becomes fugitive and
migrates from the polymeric body to provide the desired degree of
insect-active action in the localized environment. The assembly can
be affixed directly to the garment of a person by a variety of
means including adhesive coatings and hook-and-loop fasteners. The
major advantage of such an assembly is that it provides a degree of
insect activity without direct skin contact with the insect active
agents.
However the process by which this insect-active assembly is
prepared, as demonstrated by the examples#1 & #2 of U.S. Pat.
No. 4,752,477, exhibit certain manufacturing processes which could
raise potential OSHA and environmental concerns. These concerns
result from the high temperature blending of the insect-active
composition with the polymeric body of the assembly. The technique
described in examples #1 and #2 of U.S. Pat. No. 4,752,477, dearly
demonstrate that very high temperatures (i.e. 300 degrees C.) are
employed in order to attain the alloying, blending or intimate
mixing of the two required components. However this high
temperature blending process may result in the rapid loss of the
expensive insect-active composition due to volatilization in the
plant. As a direct consequence, problems of worker exposure to high
levels of volatile fumes during high temperature processing may be
expected. Such exposure could give rise to OSHA concerns.
Additionally, the loss of such volatile and potentially toxic
insect-active components to the atmosphere outside the plants
parameter, could raise significant EPA concerns.
It became clear that an improved low temperature process was needed
to avoid these high temperature processing problems; while still
retaining the insect-active efficacy of the assembly. The instant
invention represents such a significant improvement in the process
for the preparation of the assembly described in U.S. Pat. No.
4,752,477.
SUMMARY OF THE INVENTION
An improved fabrication process, for the preparation of an
insect-active assembly described in U.S. Pat. No. 4,752,477, has
been developed which facilitates the incorporation of the
insect-active composition into the polymeric body at significantly
lower temperatures. These temperatures include, but not limited to
room temperature i.e. 25 degrees centigrade). This is to be
compared to the 200-300 degree centigrade range employed and
described in U.S. Pat. No. 4,752,477. The key element of the
improved process involves the specific use of thermoplastic latex
to form the polyrnefic body. Typical of such latices are PVC, CPVC,
ABS, styrene Acrilonitfile copolymers, butadiene acrylonitrile
coplymers, acrylate and methacrylate polymers and coplymers, vinyl
acetate acrylic polymers and coplymers, ethylene and propylene
polymers and coplymers, and vinyl acetate olefins polymers and
copolymers. Such latices typically exhibit minimum film forming
temperatures at about room temperature to about 75 degrees
centigrade. Such thermoplastic latices are subsequently plasticized
with the insect-active composition described in U.S. Pat. No.
4,752,477 which act as a fugitive plasticizer.
As noted above, it has been observed that the components of various
insect-active compositions, either alone or in combination,
function as plasticizers for plasticizing the thermoplastic
latices, in place of conventional plasticizers. Thus when these
thermoplastic latices are plasticized with the insect-active
compositions, they further suppress the minimum film forming
temperatures of the resultant thermoplastic latex. On drying these
plasticized thermoplastic latices, which have been plasticized with
the insect-active composition, form uniform polymeric body which
are flexible films or sheets. These films or sheets require no or
minimal heating to be formed. The insect-active plasticizers
contain therein are generally considered to be "secondary
plasticizers"; which means that they are far more fugitive than
primary plasticizers. As a result these plasticizers are readily
released into the environment, as when attached to the garment.
These resultant films or sheets can the be cut or shaped to meet
the design of the specific garment configuration to which they are
attached.
The volatile insect-active composition within the assembly acts as
a fugitive plasticizer. Thus with the passage of time, the
insect-active composition mimics the action of a fugitive
plasticizer by defusing and volatilizing from the polymeric body to
achieve the desired level of insect-active action in the immediate
area in which the polymeric body is placed. The assembly is either
configured so that it can be appropriately affixed per Se to a
garment worn by a person (e.g. fashioned in the form of a head band
to be placed around a person's hat) or it can have separate means
to directly affix it to the garment worn by the person. The
improvement over U.S. Pat. No. 4,752,477, consists of the low
temperature method of manufacture of the insect-active
assembly.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
As noted above, this invention relates to an improved method of
preparing an insect-active assembly described in U.S. Pat. No.
4,752,477, which is incorporated by reference un the present
application. As described above, the assembly contains an
insect-active composition which acts as a fugitive volatile
plasticizer for the assembly. Since the plasticizer is volatile, it
migrates from the polymer body to achieve the desired level of
insect action (repellency, insecticidal action or both) in the
environment in which the assembly is placed. This can for example
be by directly affixed to a garment worn by a person. It is
generally preferred to have the insect repellent composition since
it acts to keep the insects away from the person wearing the
assembly.
As observed in U.S. Pat. No. 4,752,477 the major portion of the
assembly is a thermoplastic copolymer, such as for example
polyvinylidene chloride-polyvinyl chloride, which can be
appropriately fashioned in any desired shape or form. Suitable
alternative thermoplastic polymer and copolymers include but not
limited to, latices of PVC and it's copolymers, CPVC and it's
copolymers, ABS, styrene Acrilonitrile copolymers, butadiene
acrylonitrile coplymers, acrylate and methacrylate polymers and
coplymers, vinyl acetate acrylic polymers and coplymers, ethylene
and propylene polymers and coplymers, and vinyl acetate olefins
polymers and copolymers. Such latices typically exhibit minimum
film forming temperatures at about 15 degrees centigrade to about
100 degrees centigrade.
The insect-active components which are covered by the instant
invention include those which can function as plasticizers for the
thermoplastic latices. This includes such insect-active
compositions which are capable of being emulsified with a
surfactant and then mechanically blended into the thermoplastic
polymer latex. In an other embodiment of this invention, the
insect-active composition is directly dispersed into the latex
without any addition of surfactants, by means of high speed
agitation, stirring, shaking, mixing or a mechanical
homogenizer.
Included as appropriate insect-active compositions suitable for
this invention are the various ratios of blends of substituted and
unsubstituted hexanediols, substituted toluamides, and synthetic or
natural pyretherins, which are well recognized insect repellant
materials. Two of such preferred insect-active compositions involve
N,N'-diethyltohamide("DEET") and 2-Ethyl-1,3 Hexanediol in ratios
that vary from 0% to 100% of each of the components. The mount of
insect-active composition which can be added to the polymer body
can vary and can preferability range from about 1 to 100 parts by
weight of insect-active composition every 100 parts by weight of
polymer. Factors such as time of day, season, humidity and
temperature will determine to a large extent the type and level of
insect-active component required.
In addition to those factors described in U.S. Pat. No. 4,752,477
for effecting the extent that a fugitive plasticizer/insect-active
composition migrates from the polymer, in the instant improved
process additional factors such as, the type and level of
emulsifier present, if any, in the plasticized latex method.
Surfactants will have an effect on migration rate of insect-active
composition out of the assembly.
A preferred thermoplastic latices suitable for this invention are
those that when plasticized with a suitable insect-active
component, will exhibit low glass transition temperatures of about
room temperature (i.e. about 25 degrees centigrade); thus forming
continuous films or sheets upon drying. Typical of such preferred
latices is GEON 652; Polyvinylidehe Chloride (PVCI.sub.2)-Polyvinyl
Chloride (PVC) copolymer sold by B. F. Goodrich GEON 450X20 add
Vinyl Chloride-Acrylic Latex (from B. F. Goodrich). Additional
latices that are suitable for this improved process include Vinyl
Acetate/acrylic coplymers such as 76 RES-3077 from Union 76
Chemicals Company, acrylic copolymers such as 76 RES-6510 from
Union 76 Chemicals Company as well as all acrylic polymer latices
as well as polymer and copolymer latices of butadiene.
The foregoing is intended to supply a general description of the
present invention with the Examples which follow being used to
merely illustrate certain preferred embodiments thereof.
EXAMPLE 1
Emulsified Insect-Active Composition--as a Plasticizer for
PVCl.sub.2 Latex
Component A
A reaction vessel was charged with 15 grams of
N,N'-diethyltoluamide("DEET") and 15 grams of pyretherin (Available
as Premium PYROCYDE-175 from McLoughlin, Gormly, King &
Company) were mixed with 1 gram "Triton X-45" surfactant from Rohm
& Hass Company, which is a Octyl phenoxyethanol (5 oxyethylene
units) to form Component A employing high speed stirring.
Component B
In a separate reaction vessel are charged 18 grams of deionized
water is blended with 11/2 grams of "TRITON X-100" sold by
Rohm& Hass Company which is a Octyl phenoxyethanol (9-10
oxyethylene units) with agitation.
Components A and B are then blended together with high speed
agitation using a "Lightning type" mixer for about 1-2 hours to
form a stable emulsion of the insect-active composition.
EXAMPLE 2
The emulsified insect-active composition from Example 1 is then
slowly (over a 5 minutes) added to 100 parts of a GEON 652
Polyvinylidene Chloride-Polyvinyl Chloride Latex (from B. F.
Goodrich which contains 50 percent solids) employing high speed
agitation. The resulting stable latex contains approximately 35 phr
of insect-active composition per 100 parts of solids.
The resultant plasticized latex is then applied to a metal tray
coated with TEFLON fluorocarbon polymer. Using a "Doctor Blade"
draw down device to provide a uniform thickness, coating of 10
mils. The coating is then allowed to air dry at room temperature of
about 25 degrees centigrade over a 10 hour period. This results in
a continuous dried film or sheet containing the insect-active
composition, acting as a plasticizer, within the coalesced
Polyvinylidene Chloride-Polyvinyl Chloride film. The dried sheet of
about 5 mils is removed from the TEFLON clad tray. The resultant
plasticized sheet of Polyvinylidene chloride-Polyvinyl Chloride
(PVCl.sub.2 -PVC) resin, containing the insect-active composition,
was then coated with a pressure-sensitive adhesive and a release
paper covering. The strips were easily bonded to garments by
removal of the release paper and by then pressing and thereby
attaching the flexible film of polyvinyl chloride to the garment by
means of the pressure-sensitive adhesive coating.
EXAMPLE 3
This Example is the same as Example 2 except that the assembly of
polyvinylidene chloride-Polyvinyl Chloride resin, which was
plasticized with the insect repellent composition, coated with a
pressure sensitive adhesive. However, instead of release paper
covering, the assembly is bonded to a VELCRO hook-and loop
fastener. The resultant assembly is then adapted for use on
garments.
EXAMPLE 4
The emulsified insect-active composition from Example 1 is then
slowly added to 100 parts of a GEON 459X20 Vinyl Chloride-Acrylic
Latex (from B. F. Goodrich which contains 55 percent solids) with
high speed agitation over a 5 minute period. The resulting latex
contains approximately 33 phr of insect-active components per 100
parts of solids. This latex is then applied to a metal tray coated
with TEFLON fluorocarbon polymer. Using a "Doctor Blade" device a
uniform thickness coating of 5 mils is prepared. The resultant
coating is then allowed to air dry at room temperature of about 25
degrees centigrade over a 5 hour period. This results in a
continuous film of insect-active component acting as a plasticizer
within the coalesced Vinyl Chloride-Acrylic Latex. The dried sheet
of about 2.5 mils is removed from the metal tray clad with TEFLON
fluorocarbon polymer. The resultant sheet of Vinyl Chloride-Acrylic
resin, which was plasticized with the insect repellent composition,
was then coated with a pressure-sensitive adhesive and a release
paper covering. The strips were easily bonded to garments by
removal of the release paper and by then pressing and thereby
attaching the flexible film of Vinyl Chloride-Acrylic resin to the
garment by means of the pressure-sensitive adhesive coating.
EXAMPLE 5
The emulsified insect-active components from Example 1 is then
slowly added to 100 parts of an Acrylic Latex ("HYCAR 2600X288"
from B. F. Goodrich which contains 50 percent solids) with high
speed agitation over a 5 minute period. The resulting latex
contains approximately 35 phr of insect-active composition per 100
parts of solids. This latex is then applied to a metal tray coated
with TEFLON fluorocarbon polymer. Using a "Doctor Blade" device to
provide a uniform thickness a coating of 5 mils is prepared. The
resultant coating is then allowed to air dry at a temperature of
about 40 degrees centigrade over a 3 hour period. This results in a
continuous film of insect-active composition acting as a
plasticizer within the coalesced Acrylic Latex. The dried assembly
sheet of about 2.5 mils is removed from the metal tray clad with
TEFLON fluorocarbon polymer. The resultant assembly sheet of
Acrylic polymer, which was plasticized with the insect repellent
composition, was then coated with a pressure-sensitive adhesive and
a release paper covering. The strips were easily bonded to garments
by removal of the release paper and by then pressing and thereby
attaching the flexible Acrylic film to the garment by means of the
pressure-sensitive adhesive coating.
EXAMPLE 6
A 4 inch.times.8 inch strip of assembly prepare by means of the
process described in Example 2 is attached to the shirt sleeve of
the user by first removing the release paper and then wrapping the
assembly around the shirt sleeve. The user then employs the arm
containing the assembly to support a fishing pole while fishing for
20 minutes over a flying insect infested stream when the
temperature is 90 degrees Fahrenheit and the humidity is 60
percent. The effect of the insect-active composition was then
observed. The results were then compared with varying levels of
insect-active compositions and the results noted in the table
below.
TABLE ______________________________________ EFFECT OF ASSEMBLY
INSECT - ACTIVE CONTENT ON EFFICACY Latex Percent *IAC *IAC on phr
Effect on Insect Attack. ______________________________________ A
50% DEET/%50 35 phr 1 insect landing on Hand pyretherin A 100% DEET
35 phr 3 insect landing on Hand A 50% DEET/50% 10 phr 5 insect
landing on Hand pyretherin A **Control - Dioctyl 35 phr 10 insect
landing on Hand Phthalate ______________________________________
*Insect-Active Components = IAC **Control Conventional Plasticizer
with noinsect activity A = GEON 652, a Polyvinlidene
ChloridePolyvinyl Chloride latex supplied b B.F. Goodrich
Corporation.
The results dearly show that there is only one insect landing on
the bare hand directly adjacent to the assembly that contained a 50
phr level (blend of DEET and pyretherin) of insect-active
composition in the assembly affixed to the wrist. The results
further show only 5 landings on the hand adjacent to the assembly
that had a 35 phr level of insect-active composition in the
assembly affixed to the wrist. This is in sharp contrast with the
control assembly, where the insect active composition were replaced
with a conventional commercial plasticizer control having no
insect-active composition therein. This clearly demonstrates the
effectiveness of an assembly prepared by the improved process of
the instant invention.
* * * * *